Henry,
I suppose you don't believe in the Loch Ness monster, either, do you?
Take potshots at that ebayer 64 times if you'd like, I lampooned him myself, if you read my post carefully. I posted link that for "entertainment purposes only".
Although I did email him to find out how he knows that the 8x32 SE only had lead glass for two years and the 10x42 SE for three. I haven't been able to get the changeover dates/serial #s from Nikon despite much arm twisting.
I can't confirm or deny the lack of difference in levels of CA you found btwn the 8x30 E and 8x30 EII since I've never compared them.
I don't know if 64x is the magic number where all see the same thing through a pair of binoculars, because the last element in the optical train are still our eyes and brains. Consider the differences that users have reported in CA in the 16x70 Fuji FMT 1 & 2. That's twice the magnification that most birders use.
I've learned from reading wildly varying reports about various optical characteristics such as edge sharpness, pincushion, rolling ball, close focus distances, and even chromatic aberration, that what one person sees through a bin is not necessarily what others do through the same bin.
If you posted side by side photos of the E and EII showing what you saw through these two bins, and the photos confirmed your results, then I'd believe it.
I'll also repeat -I found that the 505xxx 8x32 SE shows more lateral color in a field test than the 501xxx 8x32 SE. Whether or not this difference would hold up at 64x, I don't know and it wouldn't matter anyhow, because I'm not using a 64x booster in the field. I have to live with what I see at 8x.
Unlike your ebayer buddy, I don't know if the 505 contains lead or lead free glass, but I do know that the 501 has lead glass. I also don't know if Ohara or whoever supplies Nikon's glass released lead free glass before it was optimized through trial and error testing and if that ended up in the 505.
Since the 550 8x32 SE was introduced in 2007-2008, and Nikon completed its transition to lead free glass in 2002, the 550 for sure has lead free glass, as does the 050 10x42 SE. So those would be the appropriate models to compare with older versions to test the differences in glass.
The SE doesn't have a compound internal focus objective, so I don't know what factor or factors explains the difference I see between the two SEs I've owned. The CA in the 505 isn't terrible by any means, but after using the 501 for years and not seeing any CA except at the edge of the field, I was surprised to see CA closer to the center in the 505 in high contrast situations.
Granted my eyes had changed over the 10 years since buying the two samples, but I compared them side by side. But knowing what I do now about the subjectivity of CA, I wouldn't take my own observations as gospel unless I was able to reproduce them in a photographic test.
What I do like better about the 505 is the greater color saturation. With the 8x30 EII, I get even better color saturation than the SE, but also more CA. The 8x30's image also looks brighter than the 8x32 SE's.
Similarly, the 10x42 LXL's image looked brighter than the 10x42 LX, and the LXL also showed more CA.
Since you discredited the lead free glass = > CA theory, when Ed came up with his > light transmission = > CA, it seemed plausible, because it agreed with what I was seeing through bins. But then you shot down that theory in 60 seconds.
So the only "theory" left (quotes because you said that you didn't have enough data to call it a theory) is your roof internal focus compound objective = > CA.
I see more CA in modern roofs than I do modern porros, so that seems plausible. But then again, so did the lead free glass and greater light transmission theories at the time.
The only problem is that it explains the higher CA in roofs, not porros. Perhaps that's good enough since most of the binoculars made today are roofs.
I notice that Tero is conspicuously absent in this debate. How does his famous quote go? Someone else used it in his signature, something like... binoculars are two tubes, just look through them.
Well, if it weren't raining, I would be outside just looking through those two tubes rather than debating these matters of grave international importance.
Henry, thanks for having patience with me and being a "guinea pig" for me and others who came up with alternative theories of CA. You're the best!
Brock, the Skeptic